Measure the Whole Range!

SF sap flow sensor

This sensor for the continuous measurement of the water absorption of trees operates according to the Granier principle. This measures the temperature difference between two needles that are arranged on top of each other, whereby the top needle is heated by a constant energy supply. The temperature difference can be converted to the water flow using an empirical formula.Two models are available depending on the degree of accuracy required:


  • SF-G, classic Granier sensor with 2 needles
  • SF-L, improved Granier sensor with 4 needles and a considerably greater degree of accuracy


The needles are available in 3 different lengths so they can be ideally adapted to the tree size. The energy supply for the upper needle is provided by a CCS power supply for up to 3 sensors. An external data logger is required to record the data. The sensors are supplied with 5 m of cable, weather protection cap and aluminium tubes. The cable can be extended to up to 20 m on request.



  • Can be used for trees with diameters of at least 2 cm
  • Sensor can be reused



Technical Specifications

Suitable for stem diameter:2 … ∞  cm15 … ∞  cm
Needle dimension:Ø: 1,5 mm
L: 33, 43, 63 mm
Ø: 1,5 mm
L: 33, 43, 63 mm



Ordering Details:

Art.-Nr.:  170050

SF-G sap flow sensor
with 2 needles

Art.-Nr.:  170053SF-L sap flow sensor
with 4 needles



Principal Office Müncheberg

Umwelt-Geräte-Technik GmbH
Eberswalder Str. 58
15374 Müncheberg
Tel.: +49 (0) 33432 7559-0

Branch South

Umwelt-Geräte-Technik GmbH
Munich Airport Business Park
Lindberghstr. 7a
85399 Hallbergmoos
Tel.: +49 (0) 811 124478-0